Stone Cold Gloat

[Jim Koepke]

I was hoping to find places in Portland, Oregon to see about getting a piece of scrap stone for lapping plane soles and to use for touching up the backs of blades and chisels. Figured since I plan to be there for the Lie-Nielsen Tool Event on Friday anyway, why not look into other things.

While looking on line, noticed there was a monument maker in the Kelso/Longview area. Went into town today to take care of a few things and decided to put a stop at his shop on the to do list.

Glad I did, $25 bucks is all it cost. It is a good 4 feet by 6 inches.

Stone Hunk.jpg

Guess I need to build a support for it.

jim

[David Christopher]

Jim, that looks like a great piece for flatening plane soles, but fasten it to something so it wont break

and great gloat

[jerry nazard]

It doesn't have your name on it....

[Tony Shea]

You think that'll give you a long enough area for the back and forth stroke? Nice gloat, just perfect for flattening soles. Well worth the $. If you find it's too short send over this way.

[James Taglienti]

Quite righteous jim
now you gotta stop by a cabinet shop and get a roached wide-belt to lay on it!

[Chen-Tin Tsai]

Wow, that's monster. How much does it weigh? I think that might just be the ticket for lapping plane soles.

BTW, I saw some glass shelving units that had a piece of tempered glass, 8"x36"x3/8" that looked like it might work at the local BORG...any thoughts to the glass? I don't know how flat they would be since my Veritas straightedge hasn't been ordered yet

[Dave Anderson NH]

Uh Jim, I'm assuming that's for your portable version?

Seriously though, if I remember correctly granite is about 160 lb/cuft. Are you going to cut it up or make a heavy duty bench for it in one piece?

[Jim Koepke]

Jim,

Since it is only 6 inches wide, I can use the rolls of PSA grits I bought. I recently met a guy that has a sander that is about 54 inches wide.

Chen-Tin,

Not sure about the glass. Many years ago most glass was rolled and not perfectly flat. Float glass was more likely to be flat. I am not sure how glass is made today. I do know that glass can flex.

Not sure how much it weighs, I am pretty sure from helping the guy put it in the back of the car that it is over 100 lbs.

Dave,

My plans are to build a heavy duty bench just to hold the stone. That way I will not have to come up with a way to lift it up onto my work bench all the time.


Now if I can just find rolls of 2500 grit wet or dry...

jim

[Randy Bonella]

Jim,
Do you still need the names and addresses of the granite places in Portland? of does this chunk take care of your needs? I'll PM the information to you tomorrow if you still need it. Not sure you could do any better here.

Randy...

[Jim Koepke]

Jim,
Do you still need the names and addresses of the granite places in Portland? of does this chunk take care of your needs? I'll PM the information to you tomorrow if you still need it. Not sure you could do any better here.

Randy...

Thanks Randy, this piece will do quite well to take care of my needs.

jim

[Richard Jones]

I have a bud that is a monument maker who gave me a couple of scraps of black granite, approx. 6" x 30". Interestingly enough, they are not dead flat, according to Mr. Starrett, but I think they're flat enough for the intended purpose. Like many others, I assumed that granite, countertop "granite", etc., would be DNF, but the pieces that I checked weren't.

BTW, my granite surface plate isn't DNF either. It's amazing the small amount of light you can see underneath a known straightedge and still have the piece within tolerance. My feeler gauges weren't thin enough to measure it, and I have some pretty thin ones...........

Just FYI.

Rich

And to add to this, I haven't found anything any flatter than my tablesaw top. I actually clamp old 6x48 sanding belts to it and start lapping.

[James Taglienti]

I will bet that glass is flat enough for our needs

[Mike Siemsen]

Modern glass is float glass. The molten glass is floated on a bed of liquid tin. The factory is about a mile long. Raw materials go in one in and windows come out the other. Here is a wiki link for more info
http://en.wikipedia.org/wiki/Float_glass
it is flat.
Mike

[Bob Glenn]

Wow, that's monster. How much does it weigh? I think that might just be the ticket for lapping plane soles.

BTW, I saw some glass shelving units that had a piece of tempered glass, 8"x36"x3/8" that looked like it might work at the local BORG...any thoughts to the glass? I don't know how flat they would be since my Veritas straightedge hasn't been ordered yet

Don't use tempered glass for flattening. I worked at a glass tempering plant for 31 years and most tempered glass is not flat to the standards that we talk about here.

What you want is untempered float glass which is the industry standard today. When glass is tempered, it is heated to 1200 to 1400 degrees F. (red hot and it can barely hold its form) It is then cooled rapidly with strong blasts of air on both sides of the glass. It is almost impossible to get the air even enough for the glass to remain flat. This sets up a balance of tension and compression in the glass that makes it extremely strong as long as that balance is not upset from a blow that pierces the tension surface.

Try to get a piece of float glass that is not tempered and at least 3/8 thick, then support it on the bottom with a flat surface. Be aware, however, if it breaks, the edges will be dangerously sharp.

[Chen-Tin Tsai]

That's what I was afraid of. I was going to buy a piece and test it against a good straightedge and feeler gauges, but if it's what you said, then I'll just forget that and look for float glass. I'll go back to looking for countertop cutoffs or other assorted granite pieces. So, just how flat should it be over the length and width of the piece? And, how do you go about testing the flatness of a piece that's longer than the straightedge?